OGLE-2018-BLG-0022: First Prediction of an Astrometric Microlensing Signal from a Photometric Microlensing Event

Abstract

In this work, we present the analysis of the binary microlensing event OGLE-2018-BLG-0022 that is detected toward the Galactic bulge field. The dense and continuous coverage with the high-quality photometry data from ground-based observations combined with the space-based {\it Spitzer} observations of this long time-scale event enables us to uniquely determine the masses $M_1=0.40\pm 0.05M_{\odot }$ and $M_2=0.13\pm 0.01M_{\odot }$ of the individual lens components. Because the lens-source relative parallax and the vector lens-source relative proper motion are unambiguously determined, we can likewise unambiguously predict the astrometric offset between the light centroid of the magnified images (as observed by the {\it Gaia} satellite) and the true position of the source. This prediction can be tested when the individual-epoch {\it Gaia} astrometric measurements are released.

10 pages, 10 figures, 4 tables

References in corpus (5)

• The Gaia mission
• Gravitational lens under perturbations: Symmetry of perturbing potentials with invariant caustics
• Spitzer as Microlens Parallax Satellite: Mass and Distance Measurements of Binary Lens System OGLE-2014-BLG-1050L
• ARTEMiS (Automated Robotic Terrestrial Exoplanet Microlensing Search) - A possible expert-system based cooperative effort to hunt for planets of Earth mass and below
• OGLE-2016-BLG-0168 Binary Microlensing Event: Prediction and Confirmation of the Micorlens Parallax Effect from Space-based Observation

Cited by in corpus (3)

• ROME/REA: A gravitational microlensing search for exo-planets beyond the snow-line on a global network of robotic telescopes
• Brown-dwarf companions in microlensing binaries detected during the 2016--2018 seasons
• Astrometric Microlensing of Primordial Black Holes with Gaia